Hot Water Runs Out Before Bath Is Full: Top Reasons and Solutions Explained

You come from the office, decide to take a bath, and turn on the hot water in your bathtub. At this moment, with surprise in your eyes, you see that hot water runs out before the bath is full. You repeat filling the tub with hot water, and it again drains out of hot water.

The scenario is both frustrating and ghostly. Thus, you must know why hot water runs out before the bath is full, even after running the faucet for hours. Also, how to stop the hot water from running out before the bath gets full?

The main reason hot water runs out without filling the bathtub is the shortage of hot water. The water heater may be hitting less than required to fill the bathtub. Also, there might be other home appliances running and consuming hot water. Also, sediment development inside the tank and damaged water supply line can cause insufficiency of hot water.

Top 5 Reasons Of Hot Water Runs Out Before Bath Is Full:

When hot water runs out without filling the bathtub, it frustrates people. Most people will try turning their on and off their faucets. Alas, all of their tries turn futile, only to see the tub getting empty. So, why the hot water runs out without filling up the bath?

Let’s explore the reasons:

Insufficient water supply:

If you keep facing the problem of hot water running out frequently, it’s due to inadequate supply. You may have shifted to a larger bathtub. Or, your family members have increased and require more hot water. So, your bathtub remains half-full or empty.

Sometimes, the water heater’s capacity becomes insufficient due to an increase in hot water demand. It happens mostly in winter when every user at home needs hot water. As it happens, the home’s water heater fails to provide enough hot water. So, it keeps running out, leaving your tub empty.

Moreover, people move to the bigger apartment but keep using the old water heater. So, the device fails to meet the increased hot water demand in larger apartments and homes.

Multiple appliances using hot water simultaneously:

Check the home appliances if your bathtub suddenly fails to fill up with hot water. Primarily, multiple home appliances run simultaneously and draw hot water. So, the heater is left will less than the required hot water for the bathtub.

It happens mostly when you run the dishwasher and laundry machines at the same time. These two appliances will draw water at high pressure. So, they leave little or no water for your shower. Also, the dishwasher requires a hot water supply for an extended period to clean the dishes. It will, thus, continue consuming hot water from the heater as long as you don’t turn off the machine. It happens because dishwashers are designed to be always ready for cleaning dishes.

Hence, whenever you see bathtubs running out of hot water how long to wait, immediately check the appliances. If you find them running, turn off their functioning.

Sediment development in water heater and supply line:

Over the years, sediments of different minerals will build up inside the water supply lines. Also, the water heater bottom will have rudiments of minerals. The problem is acuter and faster in hard water regions where the main water supply contains a high amount of minerals.

In America, 85% of localities are more or less affected due to hard water. So, your region is most likely facing the same issue. Different minerals will slowly build up in the water supply line as it happens. It limits the water-carrying capacity of the supply line.

Moreover, with time, the bottom of the water heater will see mineral development. It limits the heating efficiency of the heater. The sediments will insulate the water from the heating sources as they settle at the bottom. So, the heating time increases with water not getting enough heat.

Thus, when you turn on the bathtub faucet, you will see hot water coming slowly into it. Also, adequate water in the tank will run out while filling the bathtub. The worst thing is it uses more electricity but results in reduced efficiency.

Problems with the thermostat:

At times, the thermostat might become faulty. So, it will fail to work with the proper settings. As a result, the water heater runs slowly. Also, the thermostat will need more heat at the required temperature.

So, when you turn on the bathtub faucet, the water heater will not be ready. It will have less than the required hot water and run out without filling the tub. Moreover, the water heater will run slowly due to improper thermostat settings.

You may have set the thermostat at a lower setting. So the water is not so heated. It also causes the water to run out before the bath is complete. Also, your bathtub will have colder water.

Old and damaged water heater:

When the water heater grows older, its efficiency reduces gradually. So, it fails to heat enough water to supply all the home appliances. As the problem persists, you must check the shelf life of your water heater at home.

On average, a water heater runs with full power for 5 to 8 years. If the water heater is too old, it will become inefficient. So you will need more water to fill up the bathtub. As the water heater ages, the problem of insufficient water will become acute.

Leaks in dip tube and water supply line:

Finally, leaks in the water supply line and dip tubes are responsible for the bathtub not filling up timely. Usually, the problem happens in older homes.

The dib tube pushes the cold water toward the water heater’s bottom. So, it reaches the bottom where the heating source locates. As a result, the source will heat the water. However, a leaky dip tube will fail to push the cold water toward the tank bottom.

Hence, water will not reach near to the heating source. As it happens, the water heater will take time to heat the water. So, there will need to be more water inside the tank. Naturally, your bathtub won’t fill up with hot water.

What’s more, there could be damage or leaks on the main water supply line. The heated water will dip through the leaks and run out before filling the tub.

Solutions for Hot Water Runs Out Before Bath Is Full:

When you see water running out of the heater and the empty tub, you can fix it. The top solutions are:

Stop using multiple appliances simultaneously:

Check all the home appliances that use hot water. The tub should fill up quickly when you turn off the other devices. It is better to switch off the home appliances before your shower. It will give you enough time and water to fill the bathtub.

Usually, the water heater needs 30 to 40 minutes to heat the water. So, you should turn off all the other devices before 1-hour of your shower.

Stop leaks in the dip tube and water supply line:

If the leaky dip tube is causing the problem, you better replace it. A dip tube for a water heater is gettable at $20 to $30. So, it won’t be a costly replacement. You must ensure that the water heater is cool and turned off hours before you replace the dip tube. Or it can scald your hand.

For damages in the water supply line, you may fix it with Teflon or plumbing tape. If the leaks are large, you may need professional help.

Use the thermostat at the correct setting:

If the thermostat is causing the problem, try resetting it. Ensure it works in a higher setting to increase the water temperature. Also, for the faulty thermostat, you must replace it. Usually, it costs you $50 to change the thermostat of your old water heater.

Remove the sediment from the tank bottom:

You must eliminate the sedimental development from the bottom of the tank. The process is as follows:

  • Please switch off the water heater and disconnect it from the electric outlet. Also, allow it to cool down overnight and drain it to empty. Cooling down the heater is crucial because you may burn your hands without it.
  • After that, you should open the top of the water heater and access its bottom. You can use a scrubber to quickly scrub and eliminate all the sediment development inside the tank. Also, use a garden hose to remove all the debris after cleaning it.
  • Once you have cleaned the tank, run the cold-water supply line. It will remove the sediment. Finally, dry the tank and start reusing it.

Replace the water heater:

You must check the water heater thoroughly if nothing works to stop the hot water from running out. Is it performing as it should? Has the heater grown too old? Water heaters will run for 5 to 7 years successfully.

Once its shelf life gets over, you must replace it. This way, you can solve the problem of hot water running out without filling up the bath.

Before winter advances, you must check the supply line, water heater, and performance. If any fixing is required, perform the repair work ASAP. It will help you enjoy a comfier bath with enough hot water continuously.

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